Signet-Ring Cell Carcinoma Masquerading as Crohn’s Disease: A Diagnostic Challenge in Multifocal Colonic Strictures with Ascites

Gastrointestinal malignancies such as signet-ring cell carcinoma can mimic inflammatory bowel disease, leading to diagnostic uncertainty. We present the case of a 39-year-old woman who presented with cramping abdominal pain, watery diarrhea, and unintentional weight loss. Imaging revealed multifocal colonic strictures and pelvic ascites, initially suspected to represent Crohn’s disease. Bidirectional endoscopy showed gastric edema and colonic strictures without typical inflammatory features. Following laparoscopic-assisted subtotal colectomy for progressive obstruction, histopathology revealed diffuse infiltration of signet-ring cells consistent with metastatic gastric adenocarcinoma. This case highlights the importance of maintaining a broad differential diagnosis when atypical features are present. Clinicians should maintain a high index of suspicion for malignancy in young patients with atypical strictures, especially when accompanied by systemic features such as weight loss or ascites, even when initial endoscopic biopsies are non-diagnostic.